1. Field of the Invention
The present invention relates generally to the multimedia signal processing and more specifically to the design and implementation of a codec/device providing multiple bit streams
2. Related Art
Multimedia data is often generated from a multimedia signal (such as voice, video and/or audio signal) at one end system and transferred for reproduction at another end system over a network. Generally, the multimedia data (representing information contained in the multimedia signal) is generated using codecs/devices implemented according to standards or techniques. For example, data representing voice, video or audio may be respectively generated according to standards G.729, MPEG 4, G.711 using the corresponding codecs (coder-decoders) or proprietary methods implemented in the devices.
The multimedia data may be provided as a bit stream and transferred on packet network (e.g., cable network). The other end system implementing compatible standards may receive packets from network and reproduce corresponding multimedia signal.
The reproduction of multimedia signal at the other end system can be measured by various quality parameters. For example, in the case of speech the quality parameters like PESQ or MOS can be used. In case of video higher resolution can be used as a quality parameter.
Generally, higher quality requires a higher amount of data bits to encode the same multimedia signal resulting in a transfer of large quantity of data bits. Such transfer of higher bits may be undesirable at least some times (e.g., due to higher per bit transfer cost over a network or high potential packet drop rate at that time). Further, end systems implementing a specific standard provides a fixed quality of reproduction defined by the corresponding standard.
There is a need to provide higher quality in reproducing the information at least in some of the situations noted above.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.